[Turing_Machine]

1990 list:

1 General Motors

2 Ford Motor

3 Exxon Mobil

4 Intl. Business Machines

5 General Electric

6 Mobil

7 Altria Group

8 Chrysler

9 DuPont

Again, Exxon Mobil is the only overlap with 2020's list. (I presume that the references to "Exxon Mobil" in the 1990 and 1960 lists actually refer to pre-merger Exxon, since Mobil by itself is also on both lists).

I checked, and of the 2020 list, only AT&T, McKesson, and Exxon even existed in 1960 (Berkshire Hathaway kinda did, but they made shirts. Warren Buffet didn't come along and turn it into an investment operation until 1965.

Edit: list formatting.